Air-operated hand tool



April 1958 R'. E. DOEDEN 2,830,560

AIR-OPERATED HAND TOOL Filed Oct. 5, 1955 2 Sheets-Sheet 1 Izzy/Z711/7/11.

INVENTOR.

Z OLA/VD l. OOEQEN A TT'O BAA 5Y5- hired dtates arent ititice PatentedApr. 1.5, 195 8 AIR-OPERATED HAN D TOOL Roland E. Doedcn, Sherwood,Ohio, assignor to Doeden Tool Corp., Sherwood, Ohio, a corporation ofOhio Application Gctobcr 5, 1955, Serial No. 538,603

1 Ciaim. (Cl. 121--34) The present invention relates generally asindicated to an air-operated hand tool, and more particularly to a highspeed rotary hand tool having a drive shaft driven by a coaxiallydisposed air rotor.

It is a primary object of this invention to provide a hand tool of thecharacter indicated which is small and compact so as to be convenientlyheld in the hand and easily manipulated.

It is another object of this invention to provide a hand toolcharacterized in that the air motor therefor is a self-containedassembly which is clamped in the housing or handle of the tool.

It is another object of this. invention to provide an airoperated handtool having novel means for mutiling or silencing high-pitched whistlewhich would otherwise result from the high-speed operation of the tool.

It is another object of this invention to provide an air-operated handtool having a novel form of control valve mechanism for controlling theflow of air from a pressure inlet port into the inlet port of the airmotor.

It is another object of this invention to provide a hand tool in whichan end of the self-contained air motor is formed with an annular recesswhich registers with the air pressure supply port in the housingirrespective of the rotary position in which the air motor is clamped inthe tool housing.

It is another object of this invention to provide a hand tool in which asingle threaded thimble functions to clamp the air motor in the toolhousing and serves as a mount for an air deflector hood which causesthe. exhaust air from the motor to how longitudinally atong the driveshaftand along the tool secured thereto so as to blow dirt or otherforeign matter away from the work ing area of the tool.

Other objects and advantages of the present invention will becomeapparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, the invention,then, comprises the features hereinafter fully described andparticularly pointed out in the claim, the following description and theannexed drawings setting forth in detail certain illustrativeembodiments of the invention, these being indicative, how ever, of but afew of the various ways in which the principle of the invention may beemployed.

' In said annexed drawings:

Fig. 1 is a diametral longitudinal cross-section view showing one formof the present invention in which the air supply control valve isactuated by a pivotal lever which is squeezed in the hand during use ofthe tool;

Figs. 2 and 3 are transverse cross-section views taken substantiallyalong the lines 2--2 and 3-3, Fig. 1, respectively;

Fig. 4 is a fragmentary cross-section view of.- another form of theinvention wherein the air control valve is push-button actuated, thepush-button being arranged to be locked in air flow permitting position;

.Fig. 5 is an elevation view of the push-button mechanism as viewed fromthe righthand side thereof; and

Fig. 6 is a cross-section view of still another embodiment of thisinvention showing an angle drive unit secured to the drive shaft of thehandheld'tool.

Referring now more specifically to the drawings, and first to the formof the invention illustrated in Figs. 13, the same comprises generallycylindrical housing or handle 1 formed with an air pressure inlet port 2at one end, a cylindrical cavity 3 at the other end, a transverse bore tadjacent the inlet port 2, and passages 5 and 6 leading to the crossbore 4 from the inlet port 2. and from the bottom of the cavity 3,respectively.

Fitted into said cross bore 4 is a valve mechanism which comprises atubular ported bushing 7 which'is preferably press-fitted into the crossbore and which slidably mounts a valve member 8 therein, the valvemember extending through said bushing 7 for actuation as by means of alever 9 which is pivotally connected on pin 10 adjacent the rear end ofthe housing 1.

Said valve member 8' is formed with a packing ring,

groove which has opposed parallel conical walls disposed atapproximately a 45 angle with respect to the axis of said valve memberin which groove an O-ring 11 is mounted. As apparent, when said valvemember 8 is pressed upwardly, as shown in Fig. 1, the O-ring 11 seatsagainst the bottom inside corner of the bushing 7 to thus prevent flowof air from the inlet port into the housing cavity. When said valvemember is moved downwardly by squeezing the lever 9 against the housing1, air flow is permitted, and the lips of the valve memberat the conicalwalls of the O-ring groove serve to protect the O-ring 11 fromextrusion, since the air flow is directed around the outside of theO-ring and across the open gap formed between the aforesaid lips.

The valve member 8 is resiliently urged and held in seated position bymeans of a spring 12 which is compressed between said valve member 8 anda spring retainer and regulator member 14, said regulator member 14being formed with a screw driver slot or the like so that it may berotatably adjusted whereby either of its ports 15 may be aligned ormisaligned with the inlet passage 5. Said regulator member 14 is held inplace by means of the slotted tubular plug 16 which is threaded into thelower end of the cross bore 4, there being interposed rubber orrubber-like rings 17 and 18 between the regulator 14 and plug 16 andbetween said plug 16 and housing 1, so as to form fluid-tight seals.

The ring 17, at the same time, serves to frictionally retain theregulator 14 in desired rotary position. It can be seen that air flowthrough passages 5 and 15 can be regulated to any value from zero tofull flow simply by turning the regulator 14 to any position betweenfull misalignment to full alignment of said passage 15 relative to inletpassage 5.

Referring now to the air motor, the same is a complete self-containedassembly 29 which includes a, stator 21 providing an eccentricallydisposed chamber 23 around which laminated plastic or like vanes 24slide to form displacement cavities in well known manner. In thisparticular example of the tool, there are four vanes 24 radiallyslidably carried by a centrally disposed rotor 25. The stator 21 hasrings or motor end plates 26 and 27 secured thereto at opposite ends asby pins 22 in which i the respective anti-friction bearings 28 and 29are mounted to support the rotor 25 for free rotationwith respect to thestator assembly comprising the stator 21 and said rings or end plates 26and 27, the vanes 24 being of axial length so that the ends thereof arein close proximity to the inner-end surfaces of said rings or end plates26' and 27.

The outer end of the ring 26 is formed with an annular groove 30 andwith passages 31, the latter communicating with passages 31A andcircumferential undercut 31B of stator 21 whereby when valve member 8 isunseated air under pressure flows into the chamber 23. Said. annulargroove 30 is of diameter such that in all rotary portions of the statorassembly 21, 26, 27, said annular groove will register with the passage6 in the bottom of the cavity 3.

The periphery of the stator 21 is formed with exhaust passagespreferably in the form of transverse slots 32, and furthermore saidstator 21 and ring 27 are formed with a plurality of peripheral, axiallyextending slots 34 for flow of the exhausted air from the motortherethrough.

The outer end of the cavity 3 in housing 1 is internally threaded forengagement by a thimble which functions (1) to clamp the air motorassembly 24} in the housing 1 to seal the stator ring 26 against thebottom of the cavity, the clamping pressure being applied through theouter race of the anti-friction bearing 29; (2) to constitute a mufi'leror silencer to eliminate high-pitched whistling which otherwise wouldoccur if the exhausted air were allowed to pass directly into theatmosphere through the slots 32 and 34, the silencing being eifected bymeans of the porous sintered bronze ring 36 which is fitted into anannular recess in the end of said thimble 35; and (3) to constitute amounting means for an airdeflecting hood 37 which herein is of tubularform and arranged to cause the exhausted air to flow longitudinallyalong the chuck 33 and along a tool adapted to be gripped by the chuck.

The chuck 38 aforesaid may be of any well known form, but isillustratively shown herein as comprising a chuck body 39 threaded ontothe end of the rotor shaft 25 in abutment with the inner race of theanti-friction bearing 29. A contractible collet 40 alternately slottedfrom its opposite ends is fitted into the end of the chuck body 39.Frusto-conical cam surfaces in the body 39 and on the collet 40cooperate to contract the latter when forced axially endwise into thechuck body 39. The means for thus axially moving the collet 46 comprisea two-part nose piece assembly, the part 41 of which engages the outerend of the collet and the part 42 of which engages a shoulder of thepart 41 and has threaded engagement with the chuck body 39.

In the use of this tool, an air supply hose is connected to the inletport 2 of the housing 1 and the desired tool, such as a small, pointedgrinding element, for example, is mounted in the chuck 38. The housing 1is then grasped in one hand and operation is started by squeezing thelever 9 toward the housing 1, thus permitting air flow into the airmotor in a manner already described.

In a tool which is 4 /2" to 4% in length and with a housing ofapproximately 1%" diameter and an air pressure supply of 90 p. s. i.,the rotor 25 has a free running speed of 30,000 R. P. M. and a workingspeed, under load, of about 15 to 20,000 R. P. M.

It is to be noted that the thimble 35 has exhaust ports 43 therethrough,and in one example there are eight such ports equally spaced so as toprovide a uniformly flowing annular stream of air longitudinally alongthe chuck 33 and along the tool mounted therein toward the work area.

The embodiment of the invention shown in Figs. 4 and 5 is essentiallythe same as that shown in Figs. l'to 3, except that the air deflectorhood 45 may be shortened so that a larger grinding wheel or cutter maybe used and except that the valve bushing 46 is formed with abayonet-slot formation 47 at its upper end which cooperates with theradially projecting ends of a pin 48 which secures the push-button 49 tothe upper end of the valve member 50.

In the position of the parts illustrated in Fig. 4, the inlet port isclosed by the seating of the O-ring 11 against the bottom inside cornerof the bushing 46. When it is desired to use the tool, the operatorpushes the button 49 downwardly and then turns the same to lock thevalve member 50 in unseated position, whereupon the tool may becontinuously used without having to manually hold the button 49 in.

Referring now to Fig. 6, there is shown therein an angle drive unit 55secured to the rotor drive shaft 25. Said angle drive unit 55 includesan angle housing 56 of which one leg is held against the outer race ofanti-friction bearing 29 through a nut 57 having threaded engagementwith the thimble 58, said leg having a peripheral groove therearound inwhich is disposed a split ring 59 through which such holding of thehousing 56 is accomplished. in this case, the thimble 58 need not beprovided with the mufiler 36 and discharge ports 43 as before; instead,the leg of the angular housing 56 is formed with a groove 60 for exhaustof air from the air motor assembly 20.

Threaded onto the end of the rotor shaft 25 is a bevel pinion element 61which meshes with a bevel gear 62, the latter in turn being keyed to adrive shaft 63 journalled in the other leg of the angular housing 56 asby means of spaced-apart anti-friction bearings 64 and 65. The lower endof said drive shaft is formed as is the chuck body 39 in Fig. 1 so thatatool mounted therein will be disposed at right angles to the axis ofthe handheld tool.

Other modes of applying the principle of the invention may be employed,change being made as regards the details described, provided thefeatures stated in the following claim, or the equivalent of such, beemployed.

1 therefore particularly point out and distinctly claim as my invention:

A hand tool comprising a housing formed with an air inlet port at oneend, a cylindrical cavity at the other end, a transverse bore adjacentsuch one end, and passages leading into said bore respectively from saidinlet port and from the bottom of said cavity; a valve mechanism in saidbore including a movable valve member adapted to be manually actuatedfrom seated to unseated position to permit air flow from said inlet portinto said cavity; an air motor assembly removably fitted into saidcavity; said assembly comprising a tubular stator having aneccentrically disposed bore and an opening through the wall thereofcommunicating said bore with said cavity, motor end plates non-rotatablysecured at the respective ends of said stator and provided with bearingscoaxially disposed with respect to said cavity, one end plate engagingthe bottom of said cavity and formed with an annular recess thatregisters with the aforesaid passage in the bottom of said cavity in allrotary positions of said motor assembly in said cavity and with apassage leading from such recess into such eccentrically disposed bore,the other end plate and corresponding end of said.

stator being formed with an axially extending peripheral slot forexhaust of air from said cavity, a rotor journalled in said bearings,and a plurality of sliding vanes radially movably carried by said rotorand adapted to engage the wall of such bore whereby said rotor isrotated responsive to movement of said valve member to unseatedposition; a chuck mounted on said rotor to project axially beyond themouth of said cavity; a thimble threaded in said housing and arranged toengage the bearing of said other end plate to clamp said motor assemblyagainst the bottom of said cavity; said thimble constituting anextension of such exhaust slot; and an air deflector hood screwed ontosaid thimble to form an annular continuation of such exhaust slotextension whereby air exhausted from said air motor assembly flowsaxially along said chuck and toward the work area of a tool adapted tobe held by said chuck.

References Cited in the file of this patent UNITED STATES PATENTS

